The fairly recent concept of ex vivo expansion of hematopoietic progenitors requires the establishment of optimal culture conditions, at a low cost. Whereas current approaches use recombinant growth factors, Clarigen proposes to expand cord blood progenitors using natural source of growth factors. Donor availability remains a major issue for allogeneic transplantation. The potential of cord blood as a source of hematopoietic stem cells has become accepted, and we believe that this project represents a promising avenue to provide more material from this source. Our methodology should also considerable reduce the cost of this procedure due to the lowest consumption of recombinant growth factors. Thrombocytopenia bears a lot of risks associated with the post transplant period and is responsible for a good part of the cost of transplantation. We aim at determining ex vivo expansion conditions to produce a cell suspension with a relatively high number of cells of the megakaryocytic linage. Hematopoietic stem cell transplantation supporting dose-intense chemotherapy has a broad range of applications in the treatment of as well as in immune diseases and genetic diseases. We anticipate that this approach would generate extensive benefits in the wide field of transplantation. PROPOSED COMMERCIAL APPLICATION: In this study, the use of natural growth factors for ex vivo expansion should provide a basis for full-scale expansion of hematopoietic stem cells. By producing a graft with elevated relative number of megakaryocytic progenitors, the length of thrompenic postransplantation phase could be significantly decreased along with the cost of treatment. The potential commercial applications are in the field of hematopoietic stem cell transplantation for the treatment of malignancies (hematopoietic or solid tumors), immune diseases and genetic diseases. This methodology, by increasing the availability of hematopoietic stem cells for cord blood, would contribute to cord blood banking, cout shorten the search for compatible donors and reduce the associated expenses. [unreadable]